Bees often swarm when temperatures warm in spring and relocate. On Friday, April 1, a swarm of about 20000 bees nesting on the side of a building in Phoenix, AZ. began stinging people in the area. The swarm was very aggressive and over a dozen people were stung. One person with an allergic reaction was briefly hospitalized.
A beekeeper had been contacted to remove the hive today (Sat. April 2, 2016), but after the attack began, firefighters arrived and began spraying the bees with foam. This method will drive off the bees, but leaves a mess of foam and dead bees behind. Not all the bees can be subdued by the foam and they continue to swarm after the spray ends. In this case, the agitated bees took several hours to settle until a local beekeeper was finally able to capture the swarm. The swarm may have been Africanized or “killer bee” from the highly aggressive nature described.
People who were stung were seen swatting at the bees. This can be counterproductive as bees release alarm pheromone when injured that recruits additional stinging bees to attack the individual. The best course of action is to get inside a building or car away from the swarm.